Fiber to the home network incorporating fully connectorized optic fiber tap assembly

ABSTRACT

A fully connectorized optic fiber tap assembly is described that includes a first upstream connector interface configured to receive a downstream connector of a first upstream optic fiber line, and a first downstream connector interface configured to receive an upstream connector of a first downstream optic fiber line. The tap assembly further includes a set of service drop line connector interfaces. Moreover, an optic fiber tap of the assembly is configured to: receive an optical signal from the upstream connector interface, extract a portion of the optical signal, direct the extracted portion of the optical signal to the set of service drop line connector interfaces, and pass a remaining portion of the optical signal to the downstream connector interface. The fully connectorized optic fiber tap assembly is configured to be connected to the first upstream optic fiber line and the first downstream optic fiber line without splicing.

FIELD OF THE INVENTION

This invention relates generally to the field of fiber to the home(FTTH) networks including a series of optic fiber tap assembliesconnected by a series of optic fiber drops. More particularly, theinvention is directed to a new FTTH network featuring lower costinstallation and repair costs through the use of connectors betweenfiber drops and optic fiber tap assemblies in FTTH neighborhood areanetworks.

BACKGROUND OF THE INVENTION

Over the years user demand for higher data transmission rates have ledto the adoption of optic fiber technology for residential customers ofInternet service providers (ISPs)/data network communications carriers.The day has passed where download rates of less than a megabit areconsidered satisfactory for most residential customers. Instead, theneed to carry one or more streams of high definition video has led towide demand for multiple download data rates of 10 megabits or more.

Such demand cannot be met without substantial cost. The discussionherein focuses upon the costs associated with the physical optic fiberdistribution infrastructure comprising a set of serially connected opticfiber tap assemblies carrying high speed data from ISPs to residentialcustomers. Optic fiber distribution networks, while capable of carryingsubstantially higher volumes of data in comparison to copper wiretechnologies, are also substantially more expensive to build and repair.

One of the most vital aspects of providing high speed datacommunications connectivity is maintaining nearly continuous service. Inthe case of a rare service disruption, normal operation must be quicklyrestored. However, the cost for added assurance against consumerdissatisfaction arising from lengthy data network communications serviceoutages is extremely high.

One of the most important events to avoid is cutting an optic fiberdistribution line providing high speed data network connectivity to asubstantial number of customers. To avoid instances of cutting opticfiber, during an initial build-out of an optic fiber sub-network, aseries of bores, channels, and/or trenches are formed. Thereafter, opticfiber is fed/laid, either with or without protective conduit, at asufficient depth to ensure against damage to the optic fiber duringsubsequent activities of others—e.g., trenching operations associatedwith laying utility lines. For this reason, optic fiber distributionlines are buried several feet below grade. Moreover, where a risk ofcutting the fiber is high, the optic fiber is placed within the buriedconduit. The relatively deep placement of fiber distribution lines, fromwhich one or more residential drop fibers branch at a final stage of anoptic fiber, provides a higher level of confidence that the distributionfiber will not be damaged by digging, excavating or other activitieswithin the vicinity of the distribution lines.

On the other hand, relatively inexpensive short-depth plowing, to adepth of about a foot, and then laying optic fiber in the resultingvalley, enables relatively low-cost initial laying of an optic fiberdistribution line in comparison to horizontal bore drilling and deeptrenching approaches for laying optic fiber distribution lines. However,such initial cost savings are offset by a substantially heightened riskof costly subsequent damage to the optic fiber over the lifetime of thedistribution sub-network.

In that regard, repairing a cut optic fiber line typically involves acomplex fiber splicing operation. During the splicing operation, the twoends of adjoined optic fibers are heat-fused in a portable clean roomenvironment. The cost of splicing a single broken optic fiber isthousands of dollars. Moreover, the repair process requires use ofspecialized tools in the hands of an expert. In that case, it may takedays for such repair. In the mean time, a data network service providermust deal with irate customers without high speed data communicationservices for several hours—if not days—while waiting for completion ofrepairs to a cut optic fiber.

Ensuring the long-term satisfaction of residential customers is amultifaceted endeavor. First, the high speed data service connectivitymust be reliable. Second, in the case of connectivity interruptions,service must be quickly restored. Third, the high speed datacommunications network connectivity must be provided at a reasonablecost. The last of which, in many cases, is only possible if the initialbuild-out costs are not excessive.

Another aspect of optic fiber distribution sub-network designs is theforming of leaves corresponding to individual residential networkinterface units. One type of signal distribution element is a splitterthat provides a 1 to N distribution at a splitter point (either at a hubor a downstream local distribution point). Alternatively, a series ofoptic fiber tap assemblies, joined by optic fiber, take a specifiedportion of input signal power, which is less than half (e.g. 10 to 50percent) of an input optical power. The remaining optical power ispassed along to the next tap assembly on the series of optic fiber tapassemblies of a single optic fiber distribution line.

SUMMARY OF THE INVENTION

Embodiments of the invention are used to provide a connectorized opticfiber tap assembly structure and a optic fiber distribution sub-networkincorporating the connectorized optic fiber tap assembly structures thatinclude optic fiber connector interfaces for joining fully connectorizedoptic fiber tap assemblies and connectorized optic fiber drop lines inthe optic fiber distribution sub-network.

In particular, a fully connectorized optic fiber tap assembly isdescribed that includes a first upstream connector interface configuredto receive a downstream connector of a first upstream optic fiber line,and a first downstream connector interface configured to receive anupstream connector of a first downstream optic fiber line. The tapassembly further includes a set of service drop line connectorinterfaces. Moreover, an optic fiber tap of the assembly is configuredto: receive an optical signal from the upstream connector interface,extract a portion of the optical signal, direct the extracted portion ofthe optical signal to the set of service drop line connector interfaces,and pass a remaining portion of the optical signal to the downstreamconnector interface. The fully connectorized optic fiber tap assembly isconfigured to be connected to the first upstream optic fiber line andthe first downstream optic fiber line without splicing.

A fiber optic distribution sub-network is also described that includesone or more of the above-described fully connectorized optic fiber tapassemblies to facilitate expedited installation and repair of opticfiber distribution lines.

BRIEF DESCRIPTION OF THE DRAWINGS

While the appended claims set forth the features of the presentinvention with particularity, the invention and its advantages are bestunderstood from the following detailed description taken in conjunctionwith the accompanying drawings, of which:

FIG. 1 is a schematic diagram illustrating an exemplary residentialoptic fiber distribution sub-network incorporating connectorized opticfiber tap assembly structures;

FIG. 2 is a schematic drawing of an exemplary optic fiber tap assemblystructure incorporated into the sub-network depicted in FIG. 1;

FIG. 3 is a drawing depicting an exemplary external interface of a fullyconnectorized optic fiber tap assembly of the type depicted in FIG. 2and utilized in the optic fiber distribution sub-network depicted inFIG. 1;

FIG. 4 is a schematic drawing of an exemplary optic fiber tap assemblystructure incorporated into a n

FIG. 5 is drawing depicting an exemplary external interface of a fullyconnectorized optic fiber tap assembly of the type depicted in FIG. 4;

FIG. 6 is drawing depicting an exemplary external interface of a fullyconnectorized optic fiber tap assembly of the type depicted in FIG. 4where a pass-through fiber is separately connectorized in relation tothe optic fiber tap assembly;

FIG. 7 is an exemplary optic fiber distribution network incorporatingoptic fiber tap assemblies of the type depicted in FIGS. 4-6;

FIG. 8 is an exemplary optic fiber distribution sub-network comprising acombination of multi-fiber and single fiber runs;

FIG. 9 is an exemplary optic fiber distribution sub-network comprising acombination of fiber splices along a main distribution run, and fullyconnectorized optic fiber taps at branches of the main distribution run;and

FIG. 10 is an alternative optic fiber tap assembly where an input signalis amplified via circuitry of an active (powered) optic fiber tapassembly.

DETAILED DESCRIPTION OF THE DRAWINGS

Before describing the provided figures, in general the describedphysical optic fiber distribution infrastructure comprises a set ofserially connected optic fiber tap assemblies carrying high speed datafrom ISPs to residential customers that incorporate particularnoteworthy features. First, the series-connected optic fiber tapassemblies comprise fully connectorized optic fiber tap assemblies. Eachfully connectorized optic fiber tap assembly comprises both: (1)upstream and downstream optic fiber connector interfaces to whichcorresponding connectorized optic fiber connectors are connected to forma distribution line comprising multiple serially connected optic fibertaps in an optic fiber sub-network, and (2) service drop optic fiberconnector interfaces that provide the tapped optical signal to, forexample, a residence. The upstream/downstream connector interfaces ofthe fully connectorized optic fiber tap assembly eliminate timeconsuming field splicing operations during build-out and repair on opticfiber distribution sub-networks. The service drop line connectorinterface of the fully connectorized optic fiber tap assembly remainsunchanged. The connectorized interface on an optic fiber tap assemblystructure, providing a plug (as opposed to splice) interface to upstreamand downstream optic fiber distribution lines, contrasts with knownoptic fiber tap assemblies having distribution line interfaces thatrequire spliced (fused) connections between upstream/downstream opticfiber distribution lines and the optic fiber tap assembly structure.Connectorization of the optic fiber tap assembly distribution lineinterfaces facilitates relatively low cost repair of a damaged opticfiber distribution line connecting two serially connected optic fibertap assemblies when compared to optic fiber tap assemblies having asplice-based interface to distribution lines.

Second, the relatively easy replacement of damaged optic fiberdistribution lines arising from the above-described connectorization—asopposed to splicing—of optic fiber tap assemblies, in turn, reducescosts associated with damage to individual optic fiber distributionlines. Such costs include: (1) new optic fiber line, (2) repair servicefees, and (3) lost good-will arising customer service disruption.However, the combination of shallow depth and connectors (as opposed toline splices) significantly reduce each of the three costs associatedwith damage to an optic fiber distribution line causing a disruption ofdata communications services for customers downstream from the damage.

The significant reduction in repair costs leads to viability of layingoptic fiber distribution lines at a depth of about a foot using thesubstantially less expensive plowing method—as opposed to relativelydeep trenching at multiple (e.g. three or more) feet. Moreover, theprimary data communication lines, which connect sub-networks (e.g. blockarea sub-networks), are protected. However, the optic fiber distributionlines within a block (sub-network) are not protected (e.g., no conduitis used within the sub-network). The heightened risk/cost of potentiallyhaving to replace a damaged optic fiber distribution line is faroutweighed by the substantial cost savings associated with the initialbuild-out and subsequent repair (if needed) of the optic fiberdistribution line comprising a series of optic fiber tap assembliesconnected by optic fiber distribution lines buried at a relativelyshallow depth in comparison to a typical trench depth of multiple feet.

Additional changes to the optic fiber distribution network topologyinclude simplified interfaces between a local optic fiber distributionsub-network, having the serially arranged set of connectorized opticfiber tap assemblies, and primary data communication lines (coaxialcable or optic fiber) supplying the local sub-networks. Rather thanrunning multiple optic fiber lines within the local sub-networkscorresponding to a particular residential block, a single optic fiberdistribution line, including multiple serially connected optic fiber tapassemblies (each supporting multiple residential drop fiber lines),provides optic fiber communications connectivity for residences on theblock. The local sub-network distribution line is laid in the vicinityof adjoining back yard rear lot lines of opposing lots on a sameresidential block.

Turning to FIG. 1, an exemplary residential optic fiber distributionsub-network incorporates the above-discussed serially arrangedconnectorized optic fiber tap assembly structures. An optical lineterminal (OLT) 102 provides an interface to a primary (high capacity)communication network link serving multiple optic fiber distributionsub-networks such as the one depicted in FIG. 1. By way of example, theOLT 102 performs an electrical/optical signal conversion to render asuitable signal on the local sub-network for transmission to one of themultiple connected network interface units (NIUs) 104. The OLT 102further performs optical/electrical signal conversion on datatransmissions originating from network interface units of individualresidences. In accordance with a known GPON protocol, an output port atGPON hardware, providing a primary physical data communications link towhich the optic fiber sub-networks connect, corresponds to the OLT 102.

The OLT 102 output designated/designed to provide a particular outputpower that affects a quantity of fully connectorized optic fiber tapassemblies that may be serially connected by connectorized optic fiberdistribution lines in accordance with illustrative examples of opticfiber sub-networks incorporating connectorized optic fiber tapassemblies. Currently, two optical power levels (“B” and “C”) aresupported. The B level optical power level has a loss budget of 28 dband the C level optical power level has a loss budget of 32 db. Thus,the C level output configuration generally supports greater opticalsignal power loss—whether through optical power tapping (redirecting thelight energy to residential network interface units 104) or connectorlosses experienced at the connector interfaces of the fullyconnectorized optic fiber tap assemblies and the connectorized opticfiber distribution lines connecting the fully connectorized optic fibertap assemblies.

The following are exemplary cases of maximum fully connectorized opticfiber tap assembly chains supported by the OLT 102 whereseries-connected optical taps provide optical signals to specifiedquantities of optic fiber drop line-connected NIUs 104:

B optics—up to 7 series-connected 8 drop line optic fiber tapassemblies.

-   -   up to 12 series-connected 4 drop line optic fiber tap        assemblies.    -   up to 16 series-connected 2 drop line optic fiber tap        assemblies.

C optics—up to 10 series-connected 8 drop line optic fiber tapassemblies.

-   -   up to 16 series-connected 4 drop line optic fiber tap        assemblies.    -   up to 20 series-connected 2 drop line optic fiber tap        assemblies.

In the exemplary embodiment, a single optic fiber 108 connects the OLT102 to a fiber patch panel 106 of known design. The fiber patch panel106 in certain installations provides an above ground enclosure housingone or more connection points between an originating optical signalinterface of the OLT 102, carried by the single optic fiber 108, and asingle optic fiber 109 corresponding to the first link of a optic fiberdistribution sub-network comprising a series of linked connectorizedoptic fiber tap assemblies. In the illustrative example, the singleoptic fiber 109 comprises a connector 109 a that mates with acomplementary connector interface provided by an upstream connector 110a of a connectorized optic fiber tap 110.

The fiber patch panel 106, in practice, may comprise multiple lines,such as the single optic fiber line 108, connected to an OLT such as theOLT 102. The fiber patch panel 106, in practice, may further comprisemultiple single optic fiber lines coupled to a correspondingsub-network, such as the single optic fiber 109, connected thesub-network of FIG. 1 comprising the connectorized optic fiber tap 110.

The illustrative example in FIG. 1 depicts an optic fiber distributionsub-network including a set of serially connected fully connectorizedoptic fiber tap assemblies 110, 111, 112, 113, 114, 115, 116. Theconnectorized optic fiber tap assemblies 110-116 are passivedevices—i.e. they have no source of power other than the optical energycarried by the input signal. As such, the output signal power of eachtap is decreased as a result of: (1) optical signal power tapped fortransmission to optically coupled ones of the NIUs 104, and (2) opticalsignal losses arising from connection interfaces. Thus, the number oftotal serially chained optic fiber tap connections is limited by opticalsignal losses at each one of the optic fiber tap assemblies 110-115.

The connector interfaces of the fully connectorized optic fiber tapassemblies 110-116 include factory-installed, low signal power loss,connector interfaces that facilitate joining connectorized optic fiberdistribution lines that couple neighboring ones of the seriallyconnected optic fiber tap assemblies 110-116. In that regard, each fullyconnectorized optic fiber tap (e.g., optic fiber tap 110) includes anupstream optic fiber connector (e.g. upstream optic fiber connector 110a for optic fiber tap 110) and a downstream optic fiber connector (e.g.downstream optic fiber connector 110 b for optic fiber tap 110). Thus,connectorized optic fiber tap 111 includes upstream optic fiberconnector 111 a and downstream optic fiber connector 111 b. Each of theremaining connectorized optic fiber tap assemblies 112, 113, 114, 115and 116 also include the aforementioned upstream and downstream opticfiber connectors.

Moreover, connector interfaces of the fully connectorized optic fibertap assemblies 110-116 have a wavelength window of 1260 nm to 1620 nm.As a consequence, the connectorized optic fiber tap assemblies may be tobe used with any one of a variety of FTTH protocols including, but notlimited to: BPON, GPON, EPON, NGPON2, and RFOG.

The fully connectorized optic fiber tap assemblies 110-116 can be usedby any over-the-land data communications services providers that providedata connectivity via FTTH sub-networks. The fully connectorized opticfiber tap assemblies 110-116 are passive devices, and thus no externalpower or batteries are generally needed. The connectorized optic fibertap assemblies 110-116 can be mounted in a buried plantpedestal/enclosure or mounted to a pole or stand in an aerial plantapplication. The fully connectorized optic fiber tap assemblies 110-116are temperature hardened to withstand placement outdoors with noenvironmental conditioning.

In accordance with an aspect of exemplary configurations of the opticfiber tap assemblies 110-116, a variable percentage of total input poweris “tapped” by individual ones of the serially connected optic fiber tapassemblies 110-116. By way of example, since the available input opticalpower decreases at each optic fiber tap output, as a general rule thepercentage of total input optical power tapped is lowest at the firstfully connectorized optic fiber tap assembly (e.g. optic fiber tapassembly 110) and the tapped percentage of input power increases atsubsequently encountered ones of the remaining fully connectorized opticfiber tap assemblies 112, 113, 114, 115. The last fully connectorizedoptic fiber tap assembly 116 in the chain of optic fiber tap assembliesmay be configured to tap and split all the remaining optical signalpower. The tapped percentage may also vary in accordance with the numberof connected optic fiber drop lines from any given one of the fullyconnectorized optic fiber tap assemblies 110-116. Moreover, in aparticular embodiment that is based upon an active optic fiber tapassembly component (see FIG. 10 described herein below), the percentageof tapped optical power at each one of the fully connectorized opticfiber tap assemblies is dynamically configured based upon signal levelfeedback provided by at least one NIU 104 connected to each one of thechain of fully connectorized optic fiber tap assemblies 110-116.Additionally, the active optic fiber tap performs responsive/on-demandamplification of the input signal to ensure sufficient optical signalstrength in the output signal for all downstream optical fiber tapsand/or receivers (e.g. NIU 104) on the sub-network.

A set of connectorized optic fiber distribution lines 121, 122, 123,124, 125, 126 and 127 couple pairs of the serially-connected fullyconnectorized optic fiber tap assemblies 110-116. Each of theconnectorized optic fiber distribution lines 121-127 includes acorresponding upstream connector interface 121 b, 122 b, 123 b, 124 b,125 b, 126 b and 127 b. Each of the connectorized optic fiberdistribution lines 121-127 includes a corresponding downstream connectorinterface 121 a, 122 a, 123 a, 124 a, 125 a, 126 a and 127 a. As notedabove, the connectorized optic fiber distribution lines 121-127 areburied at a relatively shallow depth of about a foot. This burial depthdiffers from typical installation depths of over two feet to ensureagainst cutting/damage after build-out of the optic fiber distributionsub-network.

The connectorized interfaces of the optic fiber distribution lines121-127 exhibit a relatively lower signal loss than connectorizedinterfaces of optic fiber drop lines between NIU's and the connectorizedoptic fiber tap assemblies 110-116. For example the connector interfacesof the optic fiber distribution lines 121-127 are SC/APC connectors (SCangled polished connector). The loss characteristics of the SC/APCconnectors are generally better than the loss characteristics of theinterface connectors of the optic fiber tap assemblies to whichresidential optic fiber drops are connected for the NIUs 104. Ingeneral, given the introduction of significant signal losses at theoptic fiber distribution line connections between serially connectedfully connectorized optic fiber tap assemblies (e.g. optic fiber tapassemblies 110 and 111), the connectorized optic fiber distributionlines 121-127 use a low loss connector, such as SC/APC, on both opticfiber ends.

The system schematically depicted in FIG. 1 generally depicts anexemplary sub-network comprising a series of connectorized optic fibertap assemblies serially coupled together using connectorized optic fiberdistribution lines. Thus, the above description is meant to be exemplaryin nature—as opposed to being exhaustive—since the described elements,with the exception of connectorized optic fiber tap assemblies, aregenerally known in the optic fiber distribution network infrastructurefield.

Having described structural/functional elements of an exemplary opticfiber distribution sub-network, attention is directed to the fullyconnectorized optic fiber tap assembly structures. Turning to FIG. 2, aschematic drawing is provided of the fully connectorized optic fiber tapassembly 110. As previously explained, the fully connectorized opticfiber tap assembly 110 provides optic fiber drop line connectivitybetween a customer's NIU (e.g. NIU 104) and the optic fiber distributionline 109 of the optic fiber distribution sub-network (see FIG. 1). Thefully connectorized optic fiber tap assembly 110 includes an optic fibertap 200 configured to redirect a portion (e.g. 10-50 percent) of theoptical energy carried on an internal optic fiber line 202 of theupstream connector 110 a. Thereafter, an optical splitter structure 204evenly distributes the redirected optical energy via lines 206, 208, 210and 212 to a set of residential drop line connectors 215, includingindividual physical optic fiber line connector interfaces 216, 218, 220and 222. As the first optic fiber tap in the series of optical taps, theoptic fiber tap 200 receives a relatively high power optical signal (incomparison to subsequent optical taps within the remaining fullyconnectorized optical tap assemblies 211-216 in the exemplarysub-network depicted in FIG. 1). Thus, minimal tapping (e.g., 10percent) of the optical power input on internal optic fiber line 202occurs. The remaining portion (e.g. 90 percent) passes via internaloptic fiber line 203 of the downstream connector 110 b. The remainingportion, subject to minimized attenuation at a connection interfacebetween the fully connectorized optic fiber tap assembly downstreamconnector 110 b and the upstream connector interface 121 b of the opticfiber distribution line 121.

Turning to FIG. 3, an exemplary physical layout for a cabinet 300housing the fully connectorized optic fiber tap assembly 110 isprovided. The cabinet 300 includes a cable management and weather seal302. A front panel of the cabinet 300 is removed to show the externaloptic fiber connector interfaces of the fully connectorized optic fibertap assembly 110. The set of residential drop line connectors 215 areshown with corresponding connectorized customer service optic fiber droplines. Optic fiber tap assembly upstream connector 110 a and optic fibertap assembly downstream connector 110 b are depicted with connectorizedoptic fiber distribution lines 109 and 121, respectively.

It is noted that the upstream and downstream optic fiber distributionlines 109 and 121 may be single fiber lines (as depicted in FIG. 3).However, the fully connectorized optic fiber tap assembly structures mayaccommodate multiple optic fiber distribution lines in a by-passarrangement. Therefore, turning to FIG. 4, in addition to a tapped opticfiber line that is connected to the assembly 400 via the input/outputconnectors 400 a/400 b, a further fully connectorized optic fiber tapassembly 400 includes a pass-through connection supported bypass-through circuitry having an external connector interface. Inparticular, an upstream optic fiber connector interface 402 is coupledto a complementary downstream optic fiber connector. Thereafter, theoptical signal received via connector interface 402 is passed throughthe assembly 400, without tapping, via optic fiber line 403. The opticalsignal passes via downstream optic fiber connector interface 404 that iscoupled to a complementary upstream optic fiber connector. The connectorinterfaces 402 and 404 are low loss to preserve optical power as thereceived optical signal is passed through the assembly 400. While signalloss will occur in the interfaces 402 and 404, the signal loss can beminimized. The advantage of such arrangement is the ability tofacilitate quick/low cost repair when the pass-through optic fiber lineis cut.

Turning to FIG. 5, the cabinet 300 is depicted wherein the fullyconnectorized optic fiber tap assembly 400 incorporates a variation ofthe optic fiber connection interface depicted in FIG. 3 wherein theinterface depicted in FIG. 3 is augmented to incorporate theupstream/downstream pass-through connection interfaces 402 and 404 (seeFIG. 4) for the pass-through fiber line connections to connectorizedoptic fiber distribution lines in accordance with the pass-througharrangement schematically depicted in FIG. 4.

Turning to FIG. 6, an exemplary cabinet 300 depicts an alternative tothe optic fiber arrangements depicted in FIGS. 3 and 5. Notably, insteadof incorporating pass-through optic fiber connector interface into thefully connectorized optic fiber tap assembly (see assembly 400 of FIG.5), two optic fiber segments 601 and 602 are connectorized and joinedtogether to form an intermediate connection 603 housed within thecabinet 300. While only a single pass-through connection isillustratively depicted, for purposes of simplifying the drawing, inpractice multiple pass-through cables are potentially connected viaconnection interfaces housed within the cabinet 300.

Turning to FIGS. 7, 8 and 9, exemplary optic fiber distributionsub-networks are depicted that show the diverse types of sub-networktopologies that are supported by the variously described optic fiber tapassemblies/cabinets described with reference to FIGS. 2-6. In FIG. 7, anexemplary network based upon the path-through structures is shownwherein a first portion 700, of the series of fully connectorized opticfiber tap assemblies, receives an optical signal carried by optic fiberdistribution line 701. The optic fiber tap assemblies of the firstportion 700, per the optic fiber tap assembly structures depicted inFIG. 4, also provide connection interfaces for a pass-through opticfiber distribution line 702 that provides optic fiber signalconnectivity to a second portion 704 of the series of optic fiber tapassemblies.

Turning to FIG. 8, yet another exemplary sub-network topology isdepicted wherein cabinets housing the fully connectorized optic fibertap assemblies also operate as branching locations for pass throughoptic fiber lines feeding downstream branches of a multi-linesub-network rooted at a fiber patch panel 800.

Turning to FIG. 9, yet another exemplary sub-network topology isdepicted wherein the sub-network comprises a set of splices (inwell-protected portions of an optic fiber distribution line) andconnectors at less protected portions of the distribution line(including in the distribution lines containing fully connectorizedoptic fiber taps for single fiber residential drop distribution linescomprising multiple segments of single fiber drop line connected viafully connectorized optic fiber tap connections.

Turning to FIG. 10, yet another illustrative example of an optic fibertap assembly is schematically depicted. In the illustrative example ofFIG. 10, a fully connectorized active optic fiber tap assembly (activetap assembly) 1000 is provided. The active tap assembly 1000 isindependently powered (i.e. does not derive operating power from theinput data signal) and responsively adapts optical signal tapping and/oramplification based upon signal level needs of downstream components.Such downstream components may be either/both optical fiber taps andnetwork interface units of individual users. The active tap assembly1000, in contrast to known optic fiber tap assembly devices, permitsresponsive adjustments to configurable parameters affecting one or moreof: the percentage of tapped optical signal, amplification of thereceived optical signal for downstream optical signal recipients (e.g.connected downstream optic fiber taps), and target wavelength selectionduring tapping.

The active tap assembly 1000, through adjustable operating parameters,facilitates varying a quantity of either/both serially connecteddownstream optic fiber taps and/or service fiber drops (customers)supported by the active on a per distribution fiber/wavelength basis.Such configurability, which is supported by the active tap assembly1000, may enable an operator to avoid a need to run an additional fiberto reach customers that may instead be serviced by extending opticalsignal reach along an existing optic fiber distribution line. Moreover,the ability to selectively tap a particular wavelength enablesconfigurable designation of signal sources for particular customers(addressed by wavelength).

With specific reference to FIG. 10, the active tap assembly 1000includes a single fiber input connector 1002 (but may include multipleinput connectors in other illustrative examples of the active tapassembly). By way of example, the single fiber input connector 1002 is apassive (i.e. non-powered) component of the assembly 1000.Alternatively, the single fiber input connector 1002 is an active (i.e.powered) device. An example of an active connector component is a smallform pluggable (SFP) connector that supports variable operation (e.g.selective signal amplification) based upon a specified input signalpower target. By way of example, the signal power target may be a singlevalue and/or multiple values specifying a signal power target range.

A set of “N” single fiber output connectors 1004 pass a conditioned(e.g. amplified) non-tapped portion of the optical signal received bythe single fiber input connector 1002 from of the active optic fiber tapassembly 1000. The output connectors 1004, like the input connector1002, may be passive or active (e.g. SFP) connectors. The multiplenature of the output connectors 1004 facilitates branching from theactive optic fiber tap assembly 1000 of a single input signal tomultiple (replicated) signals for downstream consumption by optical tapsand/or drop line end units (e.g. NIUs) along diverging paths from theactive optic fiber tap assembly 1000.

An optical wavelength tapping circuit 1008 provides coarse wave divisionmultiplexing (CWDM) and dense wave division multiplexing (DWDM)wavelength selection elements supporting wavelength selection inaccordance with GPON and NGPON2 protocols. The optical wavelengthtapping circuit 1008 selectively taps optical energy from the inputoptical signal at a configured target: (1) wavelength, and/or (2) powerpercentage. The tapped optical energy passes to an optical power sensingcircuit 1012. The optical wavelength tapping circuit 1008 passes thenon-tapped remaining energy, including non-selected wavelengthcomponents of the optical signal received by the input connector 1002,to the output connectors 1004. The optical wavelength tapping circuit1008 may additionally provide configurable (e.g. a specified gain)signal amplification for all, or a portion, of the input optical signalreceived by the input connector 1002 (e.g., amplify the non-tappedportion of the input signal output via the output connectors 1004.

An optical power sensing circuit 1012 measures the input signal powerbased upon a target wavelength optical signal provided bywavelength-specific optical tap elements within the tapping circuit1008. In the illustrative example, the optical power sensing circuit1012 operates as a configurable optical signal splitter between: (1) anoptical signal distribution circuit 1016, and (2) an optical signalcompensation and amplification element 1010. More specifically, theoptical power sensing circuit 1012, based upon a threshold (minimum)signal power need of the optical signal distribution circuit 1016(obtained through interactions with a management element 1014) providingthe optical signal to a set of service drop connectors 1020, configuresa portion of the signal power received from the wavelength tappingcircuit 1008 that is separately passed to each of the optical signaldistribution circuit 1016 and the optical signal compensation andamplification element 1010.

The optical signal compensation and amplification element 1010 providessignal correction (e.g. conversion compensation) and amplification for aremaining portion of the target optical wavelength signal (previouslytapped by the tapping circuit 1008) received from the optical powersensing circuit 1012. The optical signal compensation and amplificationelement 1010 distributes a resulting corrected and amplified opticalsignal to a set of “M” single fiber output branching port outputconnectors 1006. The output connectors 1006, in turn, provide thecorrected and amplified optical signal to a subset of distributionoptical tap cascades that branch from the active optical tap assembly1000.

The branching port output connectors 1006 permit the active tap assembly1000 to provide an optic fiber signal feed to either short side routesor provide an interface to existing passive optical tap cascades. In theillustrative example, the optic fiber signal provided to the branchingport output connectors 1006 has been converted (by the optical signalcompensation and amplification element 1010) to a particular wave lengthrequired by a connected downstream optical tap cascade. Thus, thebranching port output connectors 1006 (fed by the conditioned/amplifiedsignal provided by element 1010) enable optic fiber network data service(infrastructure) operators to transition from passive optical tapassemblies to active optical taps without changing out the entireinfrastructure at once.

Moreover, the combination of the optical signal compensation andamplification element 1010 and the output connectors 1006 eliminates aneed for pass-through ports that may be needed in sub-networks thatutilize passive optical tap assemblies, thereby eliminating a need formultiple single fiber drops passing through a same pedestal (containingthe tap assemblies) along a same route only to branch off in a differentdirection per the optic fiber sub-network topologies illustrativelydepicted in FIGS. 7 and 8.

The management element 1014 provides a communications and programmedlogic platform that defines the configurable optical signal distributionand amplification operation of the active tap assembly 1000 for a targetwavelength. In an illustrative example, the management element 1014: (1)receives any of a variety of command and/or data parameter values frominternal components of the active tap assembly 1000 and externalconfiguration-related command and data sources, (2) processes thereceived parameter values, and (3) renders configuration instructions toappropriate control elements within the active tap assembly 1000. In theillustrative example, the management element 1014 provides configurationcontrol instructions to: (1) the tapping circuit 1008, (2) the inputoptical signal power sensing circuit 1012, and (3) the optical signalcompensation and amplification element 1010. Such control instructionsissued by the management element 1014 set/modify a variety of signalparameter values, in the above-identified active components of theactive tap assembly, including: gain, percentage of signal divisionbetween multiple downstream components, target wavelengths, targetsignal levels/ranges, etc.

For example, based upon received information indicating insufficientsignal power to one or more residential users connected via the servicedrop connectors 1020, the management element 1014 issues an instructionto the optical power sensing circuit 1012 to provide a greaterpercentage of the received signal to the output feeding the service dropconnectors 1020. In a general sense, the management element 1014provides a programmable platform (operating system) for running avariety of monitoring, configuration, communications, etc. applicationssupporting the configurable functional components of the active tapassembly 1000. Such functionality includes support for: remotemonitoring, network element configuration, end user configuration,software updates, signal troubleshooting, etc.

A power module 1030 supplies power to each of the active components ofthe active tap assembly 1000 via a power supply bus 1034. The powermodule 1030 is connected to an external power source via an externalpower connection 1032. By way of example, the power module 1030 receivesAC (or DC) power via the external power connection 1032 and provides DCpower via the power supply bus 1034.

The active optic fiber tap assembly 1000 provides extraordinary signalamplification, conditioning, selection, and distribution functionalitiesthat are not needed by all optic fiber signal taps in a sub-network.Thus, one or more downstream units in a series of optical tap assembliesof a same sub-network may be passive.

Additionally, after initial build out, the fully connectorized activeoptic fiber tap assembly may allow the network operator to manage theamount of customers per wavelength and make changes to the numbers asneeded without changing the physical sub-network. For example, usingcurrent technology, a single wavelength may serve 128 customers thatconsume the entire bandwidth support by the single wavelength. However,the customers may need/demand higher individual bandwidth. To providemore individual bandwidth (capacity), a portion of the 128 user (e.g. 50customers) could be assigned to a new wavelength on the fiber. Thus,through reconfiguration of active tap assemblies such as active tap 1000of FIG. 10 (via remote configuration instructions received and processedby active optic fiber taps), an optic fiber data network serviceprovider can “move” 50 of the customers to another wavelength withoutsending anyone on-site to make any physical changes to the optic fiberdistribution network. Rather the changes resulting in the “move” arehandled via remotely issued commands/instructions processed by softwareexecuted by the active tap assemblies resulting in reconfiguration oftap assembly components responsible for tapping and forwarding portionsof a receive optical signal carried on a distribution line of thesub-network. So in practice each wavelength could have a dynamicallyshifting customer count based on capacity needs and services sold by anoptical network data services provider.

The described examples herein are not limited to use of particular typesof optic fiber lines (e.g. single or multi-mode fiber). Rather a varietyof optic fiber line types are contemplated in accordance with variousalternative implementations of optic fiber distribution sub-networks.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Exemplary embodiments are described herein known to the inventors forcarrying out the invention. Variations of these embodiments may becomeapparent to those of ordinary skill in the art upon reading theforegoing description. The inventors expect skilled artisans to employsuch variations as appropriate, and the inventors intend for theinvention to be practiced otherwise than as specifically describedherein. Accordingly, this invention includes all modifications andequivalents of the subject matter recited in the claims appended heretoas permitted by applicable law. Moreover, any combination of theabove-described elements in all possible variations thereof isencompassed by the invention unless otherwise indicated herein orotherwise clearly contradicted by context.

What is claimed is:
 1. A fully connectorized optic fiber tap assemblyfor incorporation into a distribution line of an optic fibersub-network, the fully connectorized optic fiber tap assemblycomprising: a first upstream connector interface configured to receive adownstream connector of a first upstream optic fiber line; a firstdownstream connector interface configured to receive an upstreamconnector of a first downstream optic fiber line; a set of service dropline connector interfaces; and an optic fiber tap configured to: receivean optical signal from the upstream connector interface, extract aportion of the optical signal, direct the extracted portion of theoptical signal to the set of service drop line connector interfaces, andpass a remaining portion of the optical signal to the downstreamconnector interface, wherein the fully connectorized optic fiber tapassembly is configured to be connected to the first upstream optic fiberline and the first downstream optic fiber line without splicing.
 2. Thefully connectorized optic fiber tap assembly of claim 1 furthercomprising a pass-through connector interface assembly, comprising: asecond upstream connector interface, a second downstream connectorinterface, and a optic fiber line terminated by the second upstreamconnector interface and the second downstream connector interface,wherein the pass-through connector interface assembly is configured toprovide an intermediate connectorized optic fiber link between a secondupstream optic fiber line and a second downstream optic fiber line of anoptic fiber distribution sub-network.
 3. The fully connectorized opticfiber tap assembly of claim 1 wherein the set of service drop lineconnector interfaces comprise four connector interfaces for receiving aset of four service drop lines.
 4. The fully connectorized optic fibertap assembly of claim 1 wherein the optic fiber tap assembly is apassive optic fiber tap assembly having functional components thatoperate without any electrical power.
 5. The fully connectorized opticfiber tap assembly of claim 1 wherein the optic fiber tap assembly is anactive optic fiber tap assembly comprising at least one configurableactive optical signal element.
 6. The fully connectorized optic fibertap assembly of claim 5 wherein the at least one configurable activeoptical signal element comprises an optical signal amplifier.
 7. Thefully connectorized optic fiber tap assembly of claim 5 wherein the atleast one configurable active optical signal element comprises anoptical signal tap.
 8. The fully connectorized optic fiber tap assemblyof claim 5 wherein the at least one configurable active optical signalelement comprises an optical signal splitter.
 9. The fully connectorizedoptic fiber tap assembly of claim 8 wherein the optical signal splitteris configurable to divide an input optical signal power between: anoptical signal distribution circuit providing optical signal output to aset of service drop connectors, and an optical signal amplifier circuitproviding an amplified optical signal to a downstream output connectorinterface for transmission of the amplified optical signal to adownstream distribution line of the optic fiber sub-network.
 10. Thefully connectorized optic fiber tap assembly of claim 5 furthercomprising a management component configured to communicate withexternal configuration information sources and issue configurationinstructions to specify operation of the at least one configurableactive optical signal element.
 11. An optic fiber sub-networkcomprising: a fiber patch panel; a first upstream optic fiber linesignally connected to the fiber patch panel; a first downstream opticfiber line; a first fully connectorized optic fiber tap assembly forincorporation into a distribution line of the optic fiber sub-network,the first fully connectorized optic fiber tap assembly comprising: afirst upstream connector interface configured to receive a downstreamconnector of a first upstream optic fiber line; a first downstreamconnector interface configured to receive an upstream connector of afirst downstream optic fiber line; a first set of service drop lineconnector interfaces; and a first optic fiber tap configured to: receivean optical signal from the first upstream connector interface, extract aportion of the optical signal, direct the extracted portion of theoptical signal to the first set of service drop line connectorinterfaces, and pass a remaining portion of the optical signal to thefirst downstream connector interface, wherein the fully connectorizedoptic fiber tap assembly is connected to the first upstream optic fiberline and the first downstream optic fiber line without splicing.
 12. Theoptic fiber sub-network of claim 11 further comprising: a secondconnectorized optic fiber tap assembly for incorporation into thedistribution line of the optic fiber sub-network, the secondconnectorized optic fiber tap assembly comprising: a second upstreamconnector interface configured to receive a downstream connector of thefirst downstream optic fiber line; a second set of service drop lineconnector interfaces; and a second optic fiber tap configured to:receive an optical signal from the second upstream connector interface,extract a portion of the optical signal, and direct the extractedportion of the optical signal to the second set of service drop lineconnector interfaces; wherein the second connectorized optic fiber tapassembly is connected to the first downstream optic fiber line withoutsplicing.
 13. The optic fiber sub-network of claim 12 wherein the firstdownstream optic fiber line is buried to a depth below grade on theorder of one foot.
 14. The optic fiber sub-network of claim 12comprising at least two optic fiber distribution lines running throughboth the first fully connectorized optic fiber tap assembly and thesecond connectorized optic fiber tap assembly.
 15. The optic fibersub-network of claim 12 wherein a hybrid distribution line of thesub-network comprises: a first optic fiber distribution line directlyconnected to the fiber patch panel; the first upstream optic fiber line;and the first downstream optic fiber line, wherein at least one splicedconnection exists between the first optic fiber distribution line andthe first optic fiber line.